Method of and apparatus for making molds for casting piano-plates.



H. R. SIMMS.

METHOD OF AND APPARATUS FOR MAKING MOLDS FOR CASTING PIANO PLATES.

APPLICATION FILED SEPT. 28, 1914.

1, 1 31 ,743, Patented Mar. 16, 1915.

4 SHEETS-SHEET 1.

WITNESSES:

ATTORNEYS THE NORRIS PETERS c0, PHDTO-LITHQ, WASHINGTON. 11 c H. R. SIMMS.

METHOD OF AND APPARATUS FOR. MAKING MOLDS FOR CASTING PIANO PLATES.

APPLICATION FILED SEPT. 28, 1914.

4 SHEETS-SHEET 2.

A TTORNE Y o o 00 o 0 23 2 2 070 3: 0

Kw; fimy WITNESSES:

THE NORRIS PETERS CO PHOTO-LITHOV, WASHINUTON. D. C

H. R. SIMMS. METHOD OF AND APPARATUS FOR MAKING MOLDS FOR CASTING PIANO PLATES.

APPLICATION FILED SEPT. 28, 1914. 1,1 31,743, Patented Mar. 16, 1915.

4 SHEETS-SHEET 3.

/ i VENTOR.

H. R. SIMMS. METHOD OF AND APPARATUS FOR MAKING MOLDS FOB. CASTING PIANO PLATE S.

APPLICATION FILED snr'lazs, 1914.

1,131,743. Patented Mar.16,1915.

4 SHEETS-SHEET 4- A TIIORNE K5 I/V/TNESSE'S: dZE/fifk. W w

THE NORRIS PETERS CU:- PHOTO-FITHO" WASHINGTON, D. C.

EiTA'TEtl PATENT @FlQ.

HORACE R. SIMMS. OF BACINE. WISCONSIN, ASSIGNOR TO AMERICAN SKEIN & FOUNDRY COMPANY, OF RACINE, WISCONSIN, A CORPORATION OF WISCONSIN.

METHOD OF AND APPARATUS FOR MAKING IVIOLDS FOB. CASTING EIANO-PLATES.

Specification of Letters Patent.

Patented Mar. 16, 1915.

Application filed September 28, 1914. Serial No. 863,964.

To all wlzom it may concern Be it known that I, HORACE R. Snmrs, a citizen of the United States, residing at Racine, in the county of Racine and State of Wisconsin, have invented certain new and useful Improvements in the Method of and Apparatus for Making Molds for Casting Piano-Plates, of which the following is a specification.

My invention relates to the manufacture of cast piano plates and its object is to make an improvement in the method of and apparatus employed in preparing the molds for casting such plates.

A piano plate of the type in which this invention is concerned consists of a skeleton casting provided with pins to which the strings of the piano are attached. In the past it was the general practice to first cast the plates and afterward drill holes in them in which the pins were set. As the drilling of a large number of holes in a casting is a costly and laborious operation, the attempt has been made to unite the pins with the plate during the casting operation. At first the ends of the pins were simply embedded in the green sand of the mold, the pattern being formed so as to hold the pins in proper position while the sand was being rammed around them. This method of procedure was not successful because when the pattern was removed from the mold, as, for example, in forming the mold in the molding machine, which is the most expeditious and economical manner of making molds of this sort, the pins were likely to be disturbed or pulled out of their places by the movement of the pattern. T o overcome this it has been proposed to support the pins by stationary rods on which the projecting ends of the pins rest. These rods pass up through perforations in the pattern so that the pattern slides upon the same when lowered. This method, however, is open to the objection that the rods, which are necessarily slender, are likely to become bent more or less. in which case the lowering of the pattern causes a springing or lateral displacement f the rods as a result of which the pins are frequently dislodged from the green sand or are loosened so that when the flask is removed from the molding machine they fall out or at least do not occupy the intended vertical position. Furthermore, according to this method, after the pattern has been lowered the pins are held in place in the mold only by the relatively weak adhesion of the green sand so that they are quite likely to be displaced during the subsequent handling of the mold.

The principal object of my invention is to improve upon the manufacture of piano plates having string supporting pins cast therein, by providing a method of preparing the mold by means of which the pins are reliably and accurately held in their proper positions in the mold as against any tendency to follow the pattern or to be otherwise displaced during the lowering of the pattern or subsequent thereto.

A further object is to provide a novel method of forming apertures in the plate for the keys to which the piano strings are attached and by the turning of which the strings are given the proper pitch in tuning. It was formerly customary to mount these pins outside of the metal piano plate upon the wood structure to which the plate was attached. In order to utilize the plate for bracing the keys it has been more recently the practice to extend the plate somewhat and drill apertures in the extension through which the keys project. My invention provides a method of forming these apertures during the casting operation, thereby saving the expense of drilling which is considerable.

I apprehend that my invention involves not only the novel improvements in the method of preparing the molds above referred to, but also certain improvements in molding machinery for carrying out said process, to which improvements 1 also desire to lay claim herein.

the accompanying drawings illustrate the improvements constituting my invention as employed in connection with a molding machine in which the pattern is withdrawn, by suitable apparatus, from the mold after the sand has been rammed.

Figure 1 is a view, in perspective, of a molding machine of this type, the pattern of which is constructed in accordance with my invention. Fig. 2 is a plan view of one member of the flask, the drag, with the mold formed therein. Fig. 3 is a view, in perspective, of the finished piano plate. Fig. 4 is a perspective view of one'of the dry sand cores used for positioning the string supporting pins in the mold. F ig- 5 is a similar fragmentary View of the core box in which a core, such as that shown in Fig. 4, is molded. Fig. 6- is a similar viewillustrating the construction of a core box for a core having a single row of pins. Fig. 7 is a cross sectional view of the core and core box shown in Fig. 6, inverted and with the members separated one from the other for the purpose of removing the core. Fig. 8 is a vertical sectional view taken through the pattern and mold showing one of the cores and the pins embedded therein. Fig. 9 is a similar sectional view on line 99 of Fig. 1. Fig. 10 is a view, corresponding to Fig. 9, showing the pattern withdrawn from the mold. Fig. 11 is a sectional view through the dry sand core and adjacent portions of the pattern illustrating a modified arrangement for positioning the core on the pattern.

Like characters of reference designate like parts in the several figures of the drawings.

The molding machine shown as a whole in Fig. 1 is, in its general design, of familiar construction consisting of a supporting structure 25, a stripping plate 26, and a pattern 27 which is raised and lowered by means of the link and toggle mechanism 28 operated by a hand lever 29.

The finished piano plate, designated 30 (Fig. 3), is shown as provided with a single row of pins '31 cast into the rib 32 and a double row of pins 31 cast into the rib 33. The plate has a fiat, thin extension 34 formed with a number of apertures 35 through which extend keys (not shown) to which the piano strings are secured. It will be obvious that the design of the plate might be materially changed without departure from my invention, such modifications involving corresponding changes in the pattern and in the construction and arrangement of the dry sand cores employed for holding the pins in position in the mold. One of these dry sand cores, namely, one of the cores with the single row of pins, together with the core box in which it is molded, is illustrated in Figs. 6 and 7. The core box is made in two sections 36, 37, and is formed in the bottom with perforations 38 adapted to receive the pins 31, the line of parting between the sections passing through the perforations. After the-pins have been put in place the core box is filled with a body of material 38 suitable for forming a dry sand core. After the core has been molded in this way the sections are separated and the core, with the pins embedded therein, is baked in the usual manner. The core is preferably wider at its inner face than across thefacein which the pins are fixed so that when in the mold it resists any tendency tofollow the pattern when the latter is, lowered. The core 40 (Fig. 4), which supports the doublerow of pins 31, is similarly molded in a corebox made up of three sections, 41, 42, 43, having a double row of perforations 44, the lines of separation between the sections extending through these perforations. The core sections thus formed, with the pins firmly embedded therein, are; placedupon the pattern before the green sand is rammed, with the pins projecting downwardly through suitable apertures. For example, I have shown the ribs of the pattern formed with elongated-slots or recesses 45 into which the pins extend. The core sections are held in position on the pattern against displacement by any suitable means. In Fig. 8 I have shown two of the pins designed to be cast into the plate, namely, the pins deisgnated 31 at the extremities of the core section 40, as extending intoperforations 46 in the pattern. In the modified arrangement illustrated in Fig. 11 the pattern, designated 47, is formed with a slot 48 long enough to include all of the pins here designated 31, and is provided with upstanding dowels 49 which enter holes in the ends of the core designated 50.

After the cores are in position the green said 51 is rammed around the pattern and the cores so that the latter are firmly em bedded in the mold. The pattern may then be lowered without danger of disturbing the pins. The slots in the pattern are preferably made wide enough so that there isno danger of the pins binding therein. The arrange ment, it willbe seen, is much superior to that in which each pin is positioned in a. separate hole in the pattern because by in this manner eliminating possible binding between the pins and pattern, there is much less danger that the withdrawal of the pattern will disturb the pins or the cores in which they are embedded.

The apertures 35 for the keys are made as follows: Dry sand cores 52, 53, assuming that the perforations 35 are grouped as shown in Fig. 3, are formed with circular nubs 54 projecting from one side thereof for a distance equal to the thickness of the extension 34 of the piano plate. These cores is rammed. with the hubs in these recesses (Fig. The cores may be held in position by any suitable means, for example, by wires 56 attached to cross pieces 57 on the drag 58. The other member of the mold, that which is formed on the core, may, generally speaking, have any desired configuration. The part overlying the nubs 54: will, however, be formed to come in close contact with said nubs so that when the iron is poured the nubs will form the apertures 35 of the casting.

The purpose of the elements described as dry sand cores is to provide an adhesion between the mold and the pins which is much greater than that aiforded by the green sand. At the same time, the cores must be of such material that they may be broken away or otherwise stripped from the pins after the casting is made. By the term dry sand cores I intend cores or holding elements for the pins adapted to be embedded in the green sand constituting the body of the mold which will have the qualities just mentioned. The exact composition of the cores is unimportant.

I claim:

1. The method of preparing a mold for casting a piano plate and uniting thereto during the casting operation pins for the piano strings, which consists in arranging on a pattern, apertured to receive the extremities of said pins, a dry sand core in which the other extremities of the pins are embedded, ramming green sand around the pattern and said dry sand core, and then separating the pattern and mold.

2. The method of preparing a mold for casting a piano plate and uniting thereto during the casting operation pins for the piano strings, which consists in arranging on a pattern, formed with an elongated slot to receive the extremities of a plurality of said pins, a dry sand core in which the other extremities of the pins are embedded, ramming green sand around the pattern and said dry sand core, and then separating the pattern and mold.

3. The method of preparing a mold for casting a piano plate and uniting thereto during the casting operation pins for the piano strings, which. consists in arranging the pins in proper spaced relation in holes in a mutiple part core box, the lines of separation between the parts of which pass through said holes, filling the core box with a material suitable for making a dry sand core, separating the core box from the core and baking the core, then placing said dry sand core on a pattern, apertured to receive the extremities of the pins, ramming green sand around the pattern and said dry sand core. and then separating the pattern and mold.

4. The method of preparing a mold for casting a piano plate and uniting thereto during the casting operation pins for the piano strings, which consists in arranging on a pattern, apertured to receive the extremities of said pins, a core in which the pins are firmly fixed, ramming green sand around the pattern and said core, and then separating the pattern and mold.

5. The method of preparing a mold for casting piano plates having apertures for the keys to which the piano strings are attached, which consists in forming a pattern for the plates with a recess of a depth as great as the thickness of the apertured portion of the plate, making a dry sand core formed with nubs having the configuration of said apertures and projecting from one side of the core a distance equal to the thickness of the plate, placing said core on the pattern over the recess with the nubs turned toward the pattern, ramming green sand around the pattern and the dry sand core so that the latter is embedded in the mold and then separating the pattern from the mold.

6. In a molding machine for making piano plates, the combination with a supporting structure and stripping plate, of a pattern and means for moving the same to Ward and away from the stripping plate, said pattern being formed with an elongated slot adapted to receive the extremities of a plurality of pins designed to be united to the plate in the casting operation, and provided also with means for positioning on the pattern a core in which the other extremities of the pins are embedded.

7. In a molding machine for making piano plates, the combination with a supporting structure and stripping plate, of a pattern and means for moving the same toward and away from the stripping plate, said pattern being formed with an elongated slct adapted to receive the extremities of a plurality of pins designed to be united to the plate in the casting operation, and provided also with means at opposite ends of said slot for positioning on the pattern a core in which the other extremities of the pins are embedded.

8. The method of preparing a mold for casting a piano plate and uniting thereto durin the casting operation pins for the piano strings, which consists in arranging on a pattern, apertured to receive the extremities of said pins, a core of a shape to be anchored in the green sand of the mold against the tendency to be pulled therefrom by the pattern, in which core the other extremities of the pins are fixed, ramming green sand around the pattern and core, and then separating the pattern and mold.

9. In a molding machine for making piano plates, the combination With a supfor positioning on the pattern a core in porting structure and a stripping plate, of which the other extremities of the pins are 10 a a pattern and means for moving the same embedded. toward and away from the stripping plate, 7 HORACE R SIMMS said pattern being apertured to receive the extremities of a plurality of pins designed WVitnesses: to be unlted to the piano plate 1n the cast VVALTEI: F.'VVALKER, mg operation, and provlded also With means ROWLAND WILLIAMS.

Copiel of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

